Procedure:
1. In a pan over low-medium heat, heat oil and melt butter. Add garlic and parsley. Simmer for about 10 minutes.
2. Add and saute onions, bell peppers, carrots, and potatoes in the garlic butter for a few minutes. Add beef and cook until browned.
4. Mix in tomato paste and liver spread and continue sautéing for a few minutes until toasted.
5. Pour in tomato sauce and beef broth. Stir until well combined. Season with salt and pepper.
6. Cut a square sheet of puff pastry into 4 equal pieces. Roll out one piece until about 2 mm thick and rectangular.
7. Place a bit of filling and grated mozzarella cheese about 1 inch from the top edges of the puff pastry. Fold in half, brush egg wash on sides, and seal the edges. Brush whole pastry with egg wash.
8. Bake in a pre-heated oven at 180 degrees Celsius for 20-25 minutes.